Ball valve

ABSTRACT

A valve of the ball type having a ported rotatable valve member (i.e., valve ball) within a valve body, and a sealing assembly which provides a seal between the body and the valve member. The sealing assembly includes a metal ring having non-metallic resilient sealing means which contacts the valve working surface of the valve ball. The fluid pressure areas of the sealing assembly are such that line pressure for flow in either direction does not cause the seal between the sealing means and the valve member to be broken. The ring is fitted and guided within the valve body in such a manner as to prevent cocking. The nonmetallic resilient sealing means carried by the metal ring provides a double seal on two concentric areas, and ducts permit communication with the space between such sealing areas from the exterior of the body. Preferably only one sealing assembly is employed, and this is located in that portion of the body which is integral with the main portion of the body, whereby the remaining welded-on body part may be applied in the final phases of manufacture without disturbing the alignment of the valve member or injury to the sealing assembly.

United States Patent Grove et al.

[4 1 Apr, w, R972 BALL VALVE [72] Inventors: Marvin H. Grove; Kee W.Kim, both of Houston, Tex.

[73] Assignee: M 8t J Valve Company, Houston, Tex.

[22] Filed: Jan. 4, 1971 21 Appl. No.: 103,642

521 user ..137/246.22,137/312,251/172,

. 251/174 511 mu ..Fl6k5/22 [58] Field 61 Search ..l37/246.22, 312;251/172, 174 [56] References Cited -UNITED STATES PATENTS 3,378,0264/1968 Oliver..... ..137/246.22 3,416,558 12/1968 Works.....

3,421,733 1/1969 Stewart ..251/174x Primary Examiner-Harold W. WeakleyAttorneyElehr, Hohbach, Test, Albritton & Herbert [57] ABSTRACT A valveof the ball type having a ported rotatable valve member (i,e., valveball) within a valve body, and a sealing'assembly which provides a sealbetween the body and the valve member. The sealing assembly includes ametal ring having non-metallic resilient sealing means which contactsthe valve working surface 'of the valve ball. The fluid pressure areasof the sealing assembly are such that line pressure for flow in eitherdirection does not cause the seal between thesealing means and the valvemember to be broken. The ring is fitted and guided within the valve bodyin such a manner as to prevent cocking. The non-metallic resilientsealing means carried by the metal ring provides a double seal on twoconcentric areas, and ducts permit communication with the space betweensuch sealing areas from the exterior of the body. Preferably only onesealing assembly is employed, and this is located in that portion of thebody which is integral with the main portion of the body, whereby theremaining welded-on body part may be applied in the final phases ofmanufacture without disturbing the alignment of the valve member orinjury to the sealing assembly.

8 Claims, 3 Drawing Figures PATENTEDAPR r 8 1972 3, 656,498 SHEET. 1 OF2 M VPVl V f1. 620w! BY [55' 14 MM "JAAY' M M 4am Arrow/5K5 BALL VALVEBACKGROUND OF THE INVENTION This invention relates generally to valvesof the ball type such as are employed for controlling flow of liquidsand gases. It is applicable to a wide range of valve sizes, includingparticularly large valves suitable for pipe transmission lines.

Valves of the ball type generally are characterized by a rotatable valvemember or ball which has a substantially continuous spherical sealingsurface, together with sealing assemblies that surround the flowpassages of the valve body and which establish sealing engagement withthe ball for open and closed positions. Each of the sealing assembliesgenerally includes a ring which is fitted within an annular recessformed in the valve body, and which is urged by spring means toward thevalve ball. In some instances the ring is made of metal or otherrelatively rigid material with an insert of non-metallic resilientmaterial for establishing sealing contact with the surface of the ball.It is generally deemed desirable to proportion the fluid pressure areason the sealing assemblies whereby a pressure resisting seal isestablished mainly upon the upstream side of the valve, with thedownstream assembly being self-relieving to avoid trapping of pressurewithin the valve body. In some instances the valve ball may befree-floating between the sealing assemblies, but in most instances theball is provided with trunnions which are journalled in the upper andlower sides of the body.

Various difficulties have been encountered with ball valves of the typejust described. Abrasive solids tend to accumulate within the valve bodyand between the sealing assemblies, with the result that such solidmaterial may find its way between the sealing assemblies and thespherical valve working surfaces of the ball, thus tending to interferewith the desired seal and causing abrasion and deterioration of thevalve sealing surfaces. It is not uncommon for a ball valve to becomeinoperative or to require excessing turning torque because ofaccumulated solids. The use of two sealing assemblies adds materially tocost of manufacture. Aside from the cost of manufacture and machining,assembly is difficult because of the necessity of ensuring properalignment between the ball and the two sealing assemblies for both openand closed positions. Assuming that the valve body is made in two parts,with one main part providing the journalling for the ball and a recessfor mounting one of the assemblies, the other assembly is generallycarried by another bolted or welded-on body part which is applied in oneof the final steps of assembly after the ball and one of the sealingassemblies has been applied. It has been found difficult to carry outsuch a welding or bolting operation without disturbing the alignment orcausing injury to one of the sealing assemblies.

In the past, block-and-bleed has been used in connection with both gateand ball valves to determine if the seals are properly functioning. Hereagain it has been deemed necessary to employ two sealing assemblies toisolate the body space between the seals. When used on gas lines,block-and-bleed is not generally employed since the discharge ofsubstantial quantities of gas may be required to reduce the bodypressure to atmospheric. Even with liquids, the amount of fluiddischarged from block-and-bleed may be objectionable.

In view of the foregoing, it is evident that there is need for animproved ball valve construction which will overcome the difficultiesoutlined above. Particularly, there is need for a simpler constructionwhich is less expensive with respect to the materials employed,machining, and assembly operations. Also there is need for improvedsealing means and for leak detection means which does not have thedisadvantages of present block-and-bleed. Also there is need for a ballvalve which is less susceptible to the action of solids carried by theline, whereby objectionable accumulation of solids does not tend tooccur as in conventional ball valves, and whereby the seal is notseriously affected when such solids are present.

SUMMARY OF THE INVENTION In general, it is an object of the presentinvention to provide an improved ball valve construction which avoidsmany of the difficulties of present conventional ball valves.

More specifically, it is an object of the invention to provide a ballvalve having simplified sealing means, and particularly with a singlesealing assembly carried by the body which establishes a seal betweenthe body and the ball for line flow in either direction.

Another object of the invention is to provide an improved ball valveconstruction which tends to avoid accumulation or entrapment of solidsfrom the line fluid in the valve body space.

Another object of the invention is to provide a valve of the above typewhich avoids excessive torque and which is'not subject to cocking of thesealing assembly during turning of the valve ball between operatingpositions.

Another object of the invention is to provide a ball valve having novelmeans for determining if the sealing means is properly functioningwithout leakage, while at the same time providing a sealing means whichhas fluid pressure areas whereby line fluid in either direction does nottend to break the desired seal.

Another object of the invention is to provide a novel ball valve sealingmeans which can be lubricated or supplied with a plastic sealant, andwhich can also be used in such a manner as to detect any leakage.

Another object of the invention is to provide a ball valve with a singlesealing assembly and with separate annular valve working surfaces on thevalve wall, whereby if certain surfaces become abraded or worn duringusage, another alternate valve working surface can be employed.

Additional objects and features of the invention will appear from thefollowing description in which the preferred embodiment has been setforth in detail in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view insection illustrating the invention, the ball or rotary valve memberbeing shown in half section and the body in full section;

FIG. 2 is an enlarged detail in section showing the sealing meansincorporated in the valve of FIG. 1; and

FIG. 3 is a perspective view illustrating the rotary valve member beforeassembly in the body.

DESCRIPTION OF THE PREFERRED EMBODIMENT The ball valve illustrated inthe drawing consists of a body 10 having aligned flow passages 11 and 12adapted to be connected with associated piping. The body space 13between the flow passages 11 and 12 is occupied by the rotatable ball orvalve member 14. This ball has a port 16 extending transversely throughthe same, which is adapted to register with the flow passages 11 and 12for full open valve position. The closed position of the ball 14 isdisplaced angularly 90 from full open position.

The body 10 may be a metal casting as illustrated, or it may befabricated by welding from mill steel shapes. Also the ball 14 is shownas a metal casting, but here again the ball may be of the fabricatedtype. Aligned trunnions 17 and 18 are provided together with journalmeans for rotation of the ball between its operating positions. Thetrunnions and associated journal means carry the thrust of line pressurewhen the valve is closed and during opening and closing operations. Thetrunnion 17 is fitted into a bore 19 formed in the valve ball, and isnon-rotatably fixed with respect to the ball by the key 21. Thustrunnion extends through a bore 20 in the body, and its exterior end isprovided with the stem 22 which connects to suitable operating means.The body also has an extension 23 which is annular in section and whichsurrounds the trunnion.

' A suitable bushing 24 or other journal means forms a bearing orjournal for trunnion l7, and above the bushing there is a sealing glandindicated generally at 26. Between bushing 24 and sealing gland 26 thereis a split spacer ring 27, and that part of the trunnion surrounded byring 27 is provided with a groove 28. A retractable pin 29 is carried bythe body extension 23, with its inner end accommodated in groove 28. Itis normally urged into the groove 28 by compression springs 31. When pin29 is retracted, the trunnion 17 may be withdrawn or applied toaccommodate assembly operations or servicing.

The sealing gland 26 in this instance consists of spacer rings 32 or 33,which may be made of suitable metal, together with sealing means 34 ofthe O-ring type, and a plurality of sprung annuluses 35 which may bemade of suitable material such as relatively hard nylon. The annuluses35 are made flat and during assembly they are dished or sprung as shownin FIG. 1 whereby their inner peripheral edges are urged into sealingengagement with the periphery of the trunnion, and their outerperipheral edges urged into sealing engagement with the surface 36 ofthe bore within which the sealing gland is accommodated. The spacebetween the O-ring 34 and the nylon annuluses 35 is preferably incommunication with the duct 37, whereby upon removing plug 38 this spacecan be vented to the atmosphere to determine whether or not leakage isoccurring past the annuluses 35. Also in place of the plug 38, asuitable pressure lubricating fitting can be applied to supply alubricant or plastic sealant. The gland assembly is held in place by theretainer 39, which is secured by suitable means such as cap screws 41.The sealing means just described is similar to that shown inapplication, Ser. No. 864,023 filed Oct. 6, 1969.

The lower trunnion 18 is fitted within the bore 42 in the lower bodyextension 43. Extension 43 is provided with the removable closure 44,and suitable sealing means 46, such as a seal of the O-ring type, servesto prevent leakage between trunnion 18 and the body. A suitablelubricant can be applied through the duct 47. The upper or inner end ofthe trunnion 18 is journalled within the bushing 48, which in turn isfitted within the valve ball. One or more washers or shims 49 and 50 areshown interposed between the ball and the adjacent portions of the bodyto ensure proper alignment.

The cast metal body illustrated consists of the medial por tion a whichmay be substantially cylindrical in form, and which is provided with theextensions 23 and 43 to mount journals for the trunnions. The bodyportion 10b merges body portion 10a with the portion 100 of smallerdiameter. Portion 10c may be a hub adapted to be secured by boltingflanges or welding to associated piping, or in some instances theassociated piping may be welded directly to the portion 10b. Portion 10dcorresponds with portion 10b, but is made as a separate part which issecured to the medial portion 10a of the body during final stages ofassembly. It likewise provides a portion 10e of reduced diametercorresponding with the portion 106. The two portions 10a and 10d areshown secured together by welding 98. As previously mentioned, in someinstances it may be desirable to employ bolting flanges in place ofwelding.

The valve ball 14 is not a complete sphere provided with a substantiallycontinuous spherical surface. As illustrated, it is formed of annularwall portions 14a and 1417 which in general conform to two cylindersintersecting with each other at right angles. A valve surface 51 isformed on the end of one of the portions 14a and conforms generally tothe surface ofa sphere generated about the center of the ball. A similarsurface 52 may be formed on the other portion 14a, or such a surface maybe omitted to simplify machining. The portions 14b are shown providedwith end surfaces 53 and 54 which may be coincident with the same sphereas that to which surface 51 is coincident. However, since surfaces 53and 54 are not required to have a scaling function, it is preferablethat they be coincident with a sphere of lesser diameter. Arcuatereinforcing ribs 55 and 56 are shown with that end ofthe portion 14b onwhich surface 51 is formed.

A single sealing assembly 59 (See FIG. 2) is carried by the body part10b and is arranged to surround the flow passage 12. The assemblyconsists of a ring 60 that is relatively rigid and made of suitablematerial such as metal. lt is slidably fitted within a recess 61machined in the body and formed to provide two concentric cylindricalsurfaces 62 and 63 on two diameters. The ring 60 is formed with a largercylindrical surface 64 which slidably fits within the surface 62, and asmaller cylindrical surface 65 which slidably fits within the surface63. Suitable sealing means 66, such as one of the resilient O-ring type,is carried by the ring 60 and prevents leakage between the surfaces 63and 65. Also sealing means 67 and 68, which again may be sealing meansof the resilient O-ring type, is carried by the ring 60 and preventsleakage between the surfaces 62 and 64. Seals 67 and 68 are spaced apartas illustrated, whereby they seal in two spaced regions. The surface 71,which normally is adjacent to the valve surface 51, is made to conformwith the surface of a cone as illustrated. Ring 60 is provided with aninsert assembly 72 made of non-metallic resilient material, and thisassembly establishes sealing engagement with the adjacent valve workingsurface 51 of the ball.

Spring means is provided for normally urging the ring 60 toward theball. in this instance compression springs 73 are distributedcircumferentially about the annular recess which accommodates ring 60,with one end of each spring engaging the annular ring shoulder 74, andthe other end engaging the shoulder 75 formed on the body.

With the sealing assembly as described above, it is evident that anannular space 77 is formed within the body recess between the seals 66,67 and 68. This space is in free communication with the body space 13through one or more ducts 78 formed in the ring 60.

The insert assembly 72 preferably is constructed as disclosed andclaimed in copending applications, Ser. No. 17,365 filed Mar. 9, 1970and Ser. No. 21,074 filed Mar. I9, 1970. More specifically, it canconsist of a rod or bar 81 which is bent in the form of a hoop or ring,and which is made of relatively hard synthetic material such as nylon orTeflon. In general, this material can have a durometer hardness of theorder of to (D scale). The nylon ring is accommodated within a recess 82formed within the metal ring 60, and its inner and outer peripheralsurfaces are engaged by the compressed more resilient annular members 84and 85. These members can be made of suitable synthetic rubber, and mayfor example have a durometer hardness of the order of 60 to 85 (Ascale). The exposed face 86 of the nylon insert is generally parallel tothe conical surface 71 of the ring 60, but is offset forwardly a slightdistance. The end faces 87 and 88 of the more resilient insert members84 and 85 are likewise finished whereby they conform to a conicalsurface parallel to the surface 71 but offset a slight distance beyondthe surface 86.

With an insert assembly as described above, the annular surfaces formedby the faces 87 and 88 of the more resilient insert members 84 and 85are normally somewhat compressed and for closed valve position they areurged into sealing engagement with the valve working surface 51 of theball. The sealing contacts are established along two concentric annularareas. It is desirable to provide means which permits communication fromthe exterior of the valve with the space between these two concentricsealing areas. For this purpose a duct 91 is shown which extends throughthe nylon ring 81 and terminates in communication with the space betweenthe two resilient O-rings 67 and 68. The latter space is in turn incommunication with duct 92 in the body, and this duct communicates withthe larger bore 93. Bore 93 may normally be closed by a plug, or may beclosed by a fitting 94 usable for introducing a suitable plasticsealant, Assuming introduction of a plastic sealant under pressure, itwill be evident that the sealant will be applied through the duct 91 andthrough the insert assembly 72 into the space between the faces 87 and88 of the resilient insert members 84 and 85, thus ensuring an effectiveseal.

To facilitate introduction of the insert assembly 72 into the metal ring60, it is desirable for one side of the accommodating recess 82 to beformed by the separate ring 96. This ring can be applied after theinsert assembly 72 has been properly positioned, with sufficient forcebeing applied to ensure proper compression of the members 84 and 85.Ring 86 can be held in place by welding 97.

Assembly of the valve can be carried out as follows. Before the bodyportion b has been secured to the remainder of the body by the weldconnection 98, the sealing assembly 59 is introduced into itsaccommodating recess, substantially as shown in FIG. 1. With the closure44 removed, the trunnion 18 is inserted part way into the bore 42, butwithout having its inner end extending within the body sufficiently farto prevent placement of the ball. Trunnion 17 is likewise inserted partway into the bore 20, with the retainer 39 removed, and without thesealing gland 26. The ball is now inserted into the body through theleft hand end as viewed in FIG. 1, and the axis of the ball aligned withthe axes of the upper and lower trunnions. At the same time one of thevalve working surface of the ball, as for example the surface 51 asshown in FIG. 1, is aligned with the flow passage 12, whereby in thefinal positioning of the ball the surface 51 is in engagement with theinsert assembly 72, with the ring 60 being moved into its accommodatingrecess with a substantial amount of compression of springs 73. Thetrunnions 17 and 18 are then moved to their final positions, with theupper end of trunnion 18 being located within the journal bushing 48,and the lower end of the trunnion 17 being located within the bore 19and engaged by the key 21. Final positioning of the trunnion 17 permitsthe pin 29 to enter the groove 28, thus locking trunnion 17 againstretraction. The parts of the sealing gland 26 are now assembled withinthe bore 36, and with the nylon annuluses 35 being dished as they areplaced in their operating positions. The retainer 39 is now applied andsecured to the body extension 23. In the assembly operations justdescribed, it is assumed that washers or shims 49 and 50 are positionedand are of proper dimensions to secure the desired alignment.

During or after the assembly operations described above, the alignmentof the ball with respect to the sealing assembly 61 is checked.Specifically, the alignment should be such that when the ball is rotated90 between full open and closed limiting position, one of the annularvalve working surface 51 of the ball is brought into proper alignmentand sealing relationship with the insert sealing assembly 72. For fullopen position the port 16 in the ball should properly register with theflow passage 11 and 12. Thereafter the remaining portion 10d of the bodyis properly positioned relative to the medial body portion 10a, and theweld 98 applied to complete the body. Although this welding operationmay cause considerable localized heating of the body, it cannotdetrimentally affeet the remote sealing assembly 72, and it cannot causeany misalignment between the sealing assembly and the annular valveworking surfaces of the ball.

As previously explained, the sealing assembly described above providessealing contacts on two concentric annular areas formed by the faces 87and 88 of the silient members 84 and 85. A characteristic of thisassembly is that when subjected to a pressure differential from the flowpassage 12, a pressure holding seal is formed by the face 87 ofresilient member 84. However, under such conditions the seal formed bythe face 88 of member 85 is self-relieving in that it will not hold anysubstantial pressure differential applied to its inner periphery. On theother hand, if a pressure differential is applied from the body space13, then a pressure seal is formed by the face 88 of resilient member 85while the face 87 of resilient member 84 is self-relieving.

Although the valve described above is bidirectional insofar as line flowis concerned, the sealing assembly 72 will maintain a seal with the ballunder all operating conditions. Assuming that the right hand side of thevalve as shown in FIG. 1 is the upstream or high pressure side, thefluid pressure area presented by the sealing assembly is such that thering 60 is urged toward the left against the ball. This is because thediameter of the cylindrical surface 63 of the body corresponds with themean diameter between the sealing areas established by the faces 87 and88'of the resilient members 84 and 85, and is greater than the diameterof face 87 of member 84. Also it is because of the self-relieving actionof resilient face 88 under such conditions. Likewise, if the left handside of the valve as shown in FIG. 1 represents the upstream or highpressure side, the fluid pressure area presented by the ring 60 willagain tend to urge the ring against the ball. This is because thediameter of the cylindrical surface 63 is slightly less than thediameter of the sealing area established by the face 88 of insert member84, and because face 87 is self-relieving. Therefore, under alloperating conditions,- fluid pressure tends to urge the sealing assemblyagainst the ball, and in addition the sealing assembly is at all timesurged toward the ball by the compression springs 73. The force of thesesprings is sufficient to establish initial sealed engagement with theball under no or low pressure conditions. Under operating conditions theball can be rotated 90 between full open and closed positions withoutexcessive torque. During such movements any gritty solids which may havebe'come associated with the valve working surfaces or sealing assemblyare given an opportunity to be dislodged into the fluid flow. Thus wearupon the valve surfaces is maintained at a minimum. Because of theconfiguration presented by the valve member, as distinguished from aball having a continuous spherical surface, there is ample space aboutthe ball for flow of line fluid as the ball is being rotated betweenclosed and open positions. Also the clearance between the sealingassembly and the ball for open position permits some line flow about theball. This flushes out any solids tending to accumulate around the ball,with the result that such solids do not accumulate to the extent thatthe ball becomes locked against or requires excessive torque forrotation.

Normally the ball is rotated 90 between full open and closed positions.A suitable stop pin is secured to the operating stem 22 to providelimits for such turning movement. In full open position it is desirableto have some clearance between ring 60 and one of the end annular faces53 or 54. In the event the valve surface 51 should become worn becauseof abrasion or erosion, the stop pin can be reset to permit operation ofthe ball between limits which bring the other surface 52 into engagementwith the sealing assembly for closed position, assuming that surface 52has been machined for this purpose.

The ribs 55 and 56 are generally considered desirable, particularly forvalves made in the larger sizes. They serve to reinforce the wall of theball surrounded by the valve surface 51.

If under operating conditions it is desired to determine if the sealingassembly is leaking, the bore 93 is vented momentarily to atmosphere andthen connected with a pressure indicator to detect any rise in pressure.Any such pressure build-up between the concentric sealing areasindicates a leak. Pressure build-up for such indication is less thanthat required to effect the self-reliveing action described above.

We claim:

1. In a ball valve, a valve body having aligned flow passages and a bodyspace between the passages, a rotatable valve member disposed within thebody space and located between the flow passages, said valve memberbeing rotatable about an axis which is perpendicular to the axes of theflow passages and having a port extending transversely through the samewhich is adapted to register with the flow passages for open valveposition, said valve member also having at least one annular valvesurface on the same conforming generally to the surface of a sphere,said annular surface being located on one closed side of the valvemember and displaced 90 with respect to the axis of the port, journalmeans for the valve member carried by the body, and an annular sealingassembly carried by the body and surrounding one of the flow passages,said sealing assembly being adapted to engage said annular valve surfacewhen the valve member is in closed position.

2. A ball valve as in claim 1 in which said sealing assembly comprises ametal ring slidably fitted within an annular recess formed in the body,the periphery of said ring being formed to provide two peripheralcylindrical surfaces formed on two different diameters, the largerdiameter cylindrical surface being nearest to the valve member and thesmaller diameter cylindrical surface being more remote from the valvemember, the annular recess being formed to provide complementarycylindrical surfaces into which the cylindrical surfaces of the ring areslidably fitted, sealing means formed of non-metallic resilient materialcarried by one end face of the ring and adapted to contact an adjacentvalve working surface of the valve member, sealing means forming afluid-tight seal between the larger diameter cylindrical surfaces of therecess and the ring, sealing means forming a seal between the smallerdiameter cylindrical surfaces of the recess and ring, there being anannular space formed between the body and the ring between saidlast-named sealing means, and spring means located within the last-namedannular space serving to urge the ring against the valve member.

3. A valve construction as in claim 2 in which the mean effectivediameter of the sealing means between the smaller diameter cylindricalsurfaces is substantially the same as the mean diameter of thenon-metallic sealing means carried by the ring.

4. A valve construction as in claim 3 together with a vent serving toestablish communication between the body space and said annular space.

5. A valve construction as in claim 3 in which the sealing means betweenthe larger diameter cylindrical surfaces is of the O-ring typeconsisting of two spaced O-rings, and means for establishingcommunication between the space between said O-rings and the exterior ofthe valve body.

6. A valve construction as in claim 2 in which the nonmetallic sealingmeans carried by the ring and adapted to contact said valve workingsurfaces includes resilient sealing members adapted to establish sealingcontact on two annular areas of different diameters, the ring and thevalve body having ducts whereby communication is established between thespace between said sealing areas and the exterior of the valve body.

7. A valve construction as in claim 1 in which the body is made of twoparts joined by welding, the one main part serving to carry said sealingassembly, the journal means for the valve member being also carried bysaid main part of the body, the welding being at that end of the bodythat is remote from the sealing assembly.

8. A ball valve as in claim 1 in which the rotatable valve member hasanother annular valve working surface located on the opposite closedside of the valve member, said valve member being rotatable to causesaid other valve working surface to establish sealing engagement withthe sealing assembly.

1. In a ball valve, a valve body having aligned flow passages and a body space between the passages, a rotatable valve member disposed within the body space and located between the flow passages, said valve member being rotatable about an axis which is perpendicular to the axes of the flow passages and having a port extending transversely through the same which is adapted to register with the flow passages for open valve position, said valve member also having at least one annular valve surface on the same conforming generally to the surface of a sphere, said annular surface being located on one closed side of the valve member and displaced 90* with respect to the axis of the port, journal means for the valve member carried by the body, and an annular sealing assembly carried by the body and surrounding one of the flow passages, said sealing assembly being adapted to engage said annular valve surface when the valve member is in closed position.
 2. A ball valve as in claim 1 in which said sealing assembly comprises a metal ring slidably fitted within an annular recess formed in the body, the periphery of said ring being formed to provide two peripheral cylindrical surfaces formed on two different diameters, the larger diameter cylindrical surface being nearest to the valve member and the smaller diameter cylindrical surface being more remote from the valve member, the annular recess being formed to provide complementary cylindrical surfaces into which the cylindrical surfaces of the ring are slidably fitted, sealing means formed of non-metallic resilient material carried by one end face of the ring and adapted to contact an adjacent valve working surface of the valve member, sealing means forming a fluid-tight seal between the larger diameter cylindrical surfaces of the recess and the ring, sealing means forming a seal between the smaller diameter cylindrical surfaces of the recess and ring, there being an annular space formed between the body and the ring between said last-named sealing means, and spring means located within the last-named annular space serving to urge the ring against the valve member.
 3. A valve construction as in claim 2 in which the mean effective diameter of the sealing means between the smaller diameter cylindrical surfaces is substantially the same as the mean diameter of the non-metallic sealing means carried by the ring.
 4. A valve construction as in claim 3 together with a vent serving to establish communication between the body space and said annular space.
 5. A valve construction as in claim 3 in which the sealing means between the larger diameter cylindrical surfaces is of the O-ring type consisting of two spaced O-rings, and means for establishing communication between the space between said O-rings and the exterior of the valve body.
 6. A valve construction as in claim 2 in which the non-metallic sealing means carried by the ring and adapted to contact said valve working surfaces includes resilient sealing members adapted to establish sealing contact on two annular areas of different diameters, the ring and the valve body having ducts whereby communication is established between the space between said sealing areas and the exterior of the valve body.
 7. A valve construction as in claim 1 in which the body is made of two parts joined by welding, the one main part serving to carry said sealing assembly, the journal means for the valve member being also carried by said main part of the body, the welding being at that end of the body that is remote from the sealing assembly.
 8. A ball valve as in claim 1 in which the rotatable valve member has another annular valve working surface located on the opposite closed side of the valve member, said valve member being rotatable to cause said other valve working surface to establish sealing engagement with the sealing assembly. 